3 New Ozone-Munching Gases Found in Atmosphere

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Three newly discovered man-made gases have joined the growing
list of chemicals that can destroy Earth's protective ozone
layer, but these new compounds likely pose little threat to ozone
because they're found in such low concentrations, a new study
reports.

The previously unknown compounds — two new chlorofluorocarbons
( CFCs )
and one new hydrochlorofluorocarbon (HCFC) — were spotted by an
international team led by researchers at the University of East
Anglia in the United Kingdom. The scientists discovered the
atmospheric gases by analyzing air samples collected at a
relatively unpolluted research station at Cape Grim, Tasmania,
from 1978 to 2012, and from instruments aboard commercial
flights.

The three compounds exist in relatively low quantities in the
atmosphere, and none appear to be drastically increasing in
concentration in recent years, said study co-author Johannes
Laube, a researcher at the University of East Anglia.

"The three compounds are not a significant threat to the ozone
layer nor have they been in the last four decades," Laube told
Live Science by email. "That is quite reassuring to know."
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The findings were published today (June 3) in the journal
Atmosphere.

Because of their destructive effect on protective ozone, use of
CFC compounds was limited in 1987 by the Montreal Protocol, and a
total global ban went into effect in 2010. The ozone layer blocks
cancer-causing UV rays. Scientists discovered a
huge ozone hole above Antarctica in the 1980s, which is now
slowly healing.

In March, Laube and his colleagues also identified new CFC and
HCFC gases that represent a more serious threat to the Antarctic
ozone hole. Before March 2014, seven CFCs and six HCFCs (which
were introduced as replacements for CFCs) were known to destroy
ozone. The count has now expanded to 12 CFCs and eight HCFCs, and
could still rise as the researchers continue to analyze
additional air samples, Laube said.

"There's a lot more man-made trace gases in the atmosphere than
we thought, and we can find out whether these are still being
emitted or not," Laube said. "This is an important and
independent control mechanism on the Montreal Protocol."

Measurements show one of the three newfound compounds may come
from Southeast Asia, Laube said.

The newly identified CFCs could be related to either legal
loopholes in the Montreal Protocol or illegal chemical
production. The Montreal
Protocol allows trace amounts of the chemicals to be
used in the production of certain products, including some types
of insecticides and cleaning solvents.

The new CFCs are related to compounds used in the production of
refrigerants, and the new HCFC is similar to products used as
coating, solvent and cleaning agents, the study reports.